1. Field of the Invention
The present invention relates to a sunshade roll screen disposed at an outer upper end of a window or opening of buildings or houses, and having functions to not only adjust the intensity of sunlight coming into a room, but also screen the interior of the room from the outside.
2. Description of the Related Art
Heretofore, sunshade roll screens capable of being unrolled from and rolled up into a storage case have been employed instead of pent roofs and stationary tents which are fixedly disposed at outer upper ends of windows or openings of buildings. One of the known sunshade roll screens is constructed below. Both ends of a winding shaft, over which a screen is rolled up from at one end, are attached to a wall surface, and the other end of the screen is fixed to a horizontal moving rod. The horizontal moving rod is supported at its both ends to upper ends of two extensible posts which are attached to the wall surface. The screen is unrolled and rolled up by rotating a speed reducer connected to an end of the winding shaft with a crank handle or an endless cord trained over a pulley of the speed reducer.
As an improvement of the above conventional sunshade roll screen, there is known such a screen (trade name; AWNING) that, instead of the two posts supporting the both ends of the horizontal moving rod, a plurality of collapsible arm links are attached at one ends thereof to a wall surface, the arm links being able to fold from and unfold into a position projecting into midair in a horizontal direction like crab legs, and the horizontal moving rod is attached to the other ends of the arm links. Such an improved sunshade roll screen includes a mechanism of always resiliently urging the collapsible arm links to unfold in a direction toward the linear state. By rotating a speed reducer connected to a winding shaft, over which the screen is rolled up, with a crank handle or an electric motor, the collapsible arm links are unfolded to resiliently urge the horizontal moving rod forward so that the screen spreads.
The conventional sunshade roll screens described above have however problems below. In the former sunshade roll screen having two posts, as the screen spreads, the posts descend while their upper ends are moved along circles. Therefore, when the sunshade roll screen is installed in a place where the spread screen becomes an obstacle to traffic, the length of the posts must be prolonged and this operation is troublesome. Further, the presence of the posts impairs an appearance aesthetically.
On the other hand, the sunshade roll screen (AWNING) having the collapsible arm links has problems below. The collapsible arm link comprises two arms, each in the form of a square pipe, which are joined with each other in a relatively pivotable manner. A coil spring is disposed in the arms and a wire rope or the like is passed through the arms in such a manner that the two arms are resiliently urged to unfold with a strong force in a direction from the collapsed state toward the linear state. The horizontal moving rod supporting the screen is therefore required to have a large sectional area and a high degree of strength so as not to flex into a bowed shape with the resiliently urging force applied from the collapsible arm link, thus resulting in larger dead weight of the horizontal moving rod. Also, the winding shaft holding the screen tightly must be made of a strong hollow shaft having a large outer diameter (usually in the range of 50 to 100 mm) so that the winding shaft will not flex into a bowed shape and the screen will not slack. As a result, the total dead weight of components of the roll screen is increased.
Further, when the collapsible arm link is unfolded solely, the unfolding operation is effected as a link motion. To prevent the horizontal moving rod from wobbling laterally to the left and right, therefore, two or more collapsible arm links are disposed in symmetrical relation like crab legs. With this structure, forces acting on the horizontal moving rod in opposite directions upon the link motions of the collapsible arm links are canceled out, and the horizontal moving rod is allowed to move in parallel relation to the wall surface while it is prevented from wobbling laterally to the left and right. However, because the sunshade roll screen utilizes the resiliently urging forces applied from the collapsible arm links for spreading the screen tightly, the screen can no longer spread evenly and the horizontal moving rod supporting the screen can no longer keep a parallel and horizontal posture with respect to the wall surface, if there occurs uneven expansion and contraction of screen cloth, or if there occurs uneven deterioration in the resiliently urging forces applied from the collapsible arm links. Consequently, when the screen is retracted, the screen is not rolled up over the winding shaft in a perpendicular direction, and the horizontal moving rod moves with one end rising to a higher level and the other end dropping to a lower level. This results in that the screen is not fully rolled up at either end and the horizontal moving rod cannot be completely returned at one end back to a predetermined storage position.
To cope with the above problem, the screen cloth is required to have such a high tensile strength as enough to prevent uneven expansion and contraction of the cloth. Generally, the screen material is a piece of cloth made of chemical fibers such as polyester fibers, and the fibers are impregnated with a coating material having a water repelling property, e.g., a fluorocarbon resin, for the purpose of suppressing expansion and contraction of the fibers. As the cloth fibers are impregnated with a larger amount of the coating material, expansion and contraction of the screen cloth is held down to a lower level. For this reason, a piece of thick cloth impregnated with a large amount of the coating material is generally employed as exterior screen cloth in usual cases. The screen using such cloth has however a disadvantage of having increased dead weight. Spreading the screen with large dead weight over an entire target area without any slack requires that the arms links are resiliently urged with a considerably strong force.
Thus, a considerably large rotating load is required to rotate the large-diameter winding shaft itself, and a driving load necessary for rolling up the screen, which is held in tightly spread state by the arm links under the strong resiliently urging forces, is further increased. Accordingly, a speed reduction ratio of the speed reducer must be set to a considerably large value to make the operating force smaller. This results in a such drawback that when the screen is manually rolled up with a crank handle or the like, the operation requires a long time and is troublesome, and when the screen is rolled up with rotation of a geared motor, the motor is required to have a large torque and a product cost is increased. Another drawback of the latter sunshade roll screen is that in the event the screen in the spread state is blown by a so strong rush of wind as to possibly damage any component of the screen and the wall surface to which the screen is attached, the rolling-up speed is too slow to retract the screen quickly if the screen is manually rolled up. Even if the screen is rolled up by an electrically-powered operation in combination with a wind gauge, the rolling-up speed of the geared motor is also not enough in many cases. In other words, satisfactory effectiveness is not achieved in match with an increase in cost.
As still another drawback, the latter sunshade roll screen is not adaptable for keeping off the low evening sun and the sunlight coming in obliquely with respect to the wall surface. Moreover, the sunshade roll screen (AWNING) having a structure to hold the collapsible arm links projecting into midair has large total weight because of large dead weights of individual components, as mentioned above, and it is fixedly bolted to the outer surface of a heavy-weight wall with a high degree of strength, such as made of iron frames, concrete, or stones. Therefore, work of installing the screen is difficult to implement and necessarily requires skilled workers in an actual situation. If the heavy-weight sunshade roll screen is installed to a light-weight outer wall of wooden houses, the wall surface may be damaged with a overload imposed on the wall surface upon passing of a rush of wind and so forth. Such a screen is hence not suitable for wooden houses. In addition to those various problems, the screen is hard to remove for cleaning. In many cases, the screen is used for a long period of time while being left dirty, which results in an unpleasant appearance from the aesthetic point of view.
With a view of improving the problems set forth above, an object of the present invention is to provide a light-weight, compact sunshade roll screen which can be installed to any type of wall surfaces with easy mounting work, and which can unroll and roll up a screen speedily with a simple operation. Further, the sunshade roll screen includes a safety device having a sensor which is responsive to even an instantaneous external pressure such as caused by a rush of wind, for example, to retract the screen into a storage state in a moment, has functions of keeping off even the light from the low sun and screening the interior of rooms from the outside, and enables the screen to be simply removed for cleaning with ease.
To that end, according to a sunshade roll screen of the present invention, hinges formed with gears held in mesh with each other are fixed to adjacent ends of two arms coupled in series. A collapsible arm link capable of folding and unfolding is constructed by the two arms through the hinges, the collapsible arm link being arranged two or more in parallel. Each of the collapsible arm links has one end angularly movably pivoted to a support pipe fixedly disposed on the wall side, and the other end angularly movably pivoted to a horizontally moving rod. Further, hinged points of the collapsible arm links are coupled to each other by a connecting rod, and a framework is constructed by the arms, the horizontal moving rod and the support pipe arranged to define quadrilateral in the form of parallelograms. Then, a roll screen capable of being unrolled and rolled up is attached onto the framework.
Also, according to a sunshade roll screen of the present invention, one ends of two arms are angularly movably pivoted in the same plane to a support pipe fixedly disposed on the wall side, and a horizontal moving rod is disposed parallel to the support pipe. Two rack gears are slidably disposed in the horizontal moving rod in an opposed relation, the two rack gears being able to move in opposed directions through an idle gear held in mesh with the two rack gears. Sliding shoes slidable in the horizontal moving rod are connected to ends of the two rack gears, and the other ends of the arms are angularly movably pivoted to the sliding shoes. A roll screen capable of being unrolled and rolled up is attached onto a framework constructed by the arms, the support pipe and the horizontal moving rod.
Moreover, in the above sunshade roll screen, a roll of the screen wound over a winding shaft is accommodated in a storage case having a slit, and has an outer periphery supported by a slit-side inner wall surface of the storage case. Additionally, when the screen swing with respect to the support pipe upon receiving an excessively strong external force, the collapsible arm links are folded automatically, or the screen is rolled up automatically.
With the sunshade roll screen of the present invention constructed as set forth above, the roll screen can be easily spread to a predetermined position by pulling down an operating with no need of lateral posts. Also, the collapsible arm links enable the horizontal moving rod to translate evenly through the connecting rods and the hinges. The weight of the roll screen and the winding shaft can be lessened, and the strength required for the support components can be reduced. Further, the roll screen can be rolled up automatically because a trigger is released from its locked state when the screen is blown by a rush of wind or the like. In addition, the roll screen is easily replaceable.